In “The One World Schoolhouse,” Salman Khan presents a simple thesis: We learn best when we learn actively and at our own pace, mastering each new skill before proceeding to the next. What sets Mr. Khan apart from most pedagogical theorists, besides the fact that he’s actually right, is that he’s giving his services away. His website, KhanAcademy.org, hosts thousands of instructional videos and interactive lessons. Millions of people around the world have used them and sing their praises.

Given his growing success, Mr. Khan’s goal is suitably ambitious: “A free, world-class education for anyone, anywhere.” But he seems to want to change the way the world learns without changing the way the world schools.

Mr. Khan’s focus is inside the classroom on instructional practices and tools. He is largely silent on, and seems indifferent to, the ways schools are managed and how students choose or are assigned to them and the way teachers are trained and compensated.